1. Field of the Invention
This invention relates in general to seamless multi-network wireless service handoffs and more particularly to automatically switching between destination device contact numbers in a call list based on network coverage type.
2. Description of the Related Art
Wireless Local Area Networks (WLANs) are typically supported by WLAN servers, which may alternatively be referred to as private branch exchanges (PBXs) or enterprise servers. The PBX normally provides a control and switching function for the WLAN and communication units operating therein or users thereof. The WLAN can be an attractive and inexpensive alternative for typical voice services such as telephony or dispatch services and may provide additional amenities such as high-speed wireless Internet and Intranet access as well as other real-time applications that may be more specific to a given enterprise.
Wireless Wide Area Networks (wireless WANs or WANs) such as conventional cellular telephone systems are also known. Such networks provide the advantage of wide area coverage but may not be economically attractive for routine access to wideband or high speed data capabilities, such as are required for certain Internet or Intranet applications. Nevertheless a communication unit that is operating on a WLAN may move beyond the effective service area for the WLAN and thus need support or services from a WAN.
Each network type—WLAN and WAN—provide a unique device identifier to each subscribing device to facilitate location of and connection to each of the wireless devices. WAN networks typically provide 10-digit identifiers, while WLANs typically provide 4-digit identifiers, but may also provide a 10-digit WLAN identifier. Connection of wireless devices through a WLAN typically does not implicate any expense to the users. However, if a first user connects to a second user by utilizing the second user's 10-digit WAN identifier, the second user will be connected through the WAN to the first user, even if both users are within a coverage area of a WLAN. Unlike the WLAN, connection through the WAN typically incurs a per-minute charge. Therefore, if a WLAN connection is available, connection of users through a WAN should be automatically avoided.
Currently, a user of an originating device must consciously consider where the originating device is currently located and where destination device might be located before placing a call. These considerations are burdensome on the originating user, waste time, create extra steps in placing a call, and often result in improper guessing by the originating user, necessitating a second attempt.
Therefore a need exists to overcome the problems with the prior art as discussed above.